The present invention relates to a process for the preparation of plates of a metallic or semimetallic material from a liquid mass by moulding and without direct contact with the walls of a container.
The preparation of semiconductor crystals in the form of plates suffers from disadvantages due to the contact between the liquid and its mould. Moreover, in crystal growth, the possible interactions between the material from which the mould is made and the liquid can lead to parasitic nucleation phenomena during solidification, as well as to mechanical stressed on cooling.
To obviate these disadvantages, use is made of processes in which the liquid mass of the material to be worked is separated from the walls of the crucible or mould by a liquid film of a second material, which is chemically inert relative to the first material, is not miscible therewith and has a good wetting power with respect to the crucible or mould walls. Vertical pulling or drawing methods already make use of the encapsulation principle (coating by an immiscible material).